Combining external beam radiotherapy with prostate brachytherapy: issues and rationale.

a he optimal treatment for clinically localized prostate cancer remains controversial. For paients with low-risk prostate cancer (Stage T1c2a, Gleason score less than 7, prostate-specific ntigen [PSA] of 10.0 ng/mL), monotherapy with adical prostatectomy, three-dimensional conforal radiotherapy (3D-CRT), intensity-modulated T, or prostate brachytherapy results in similar iochemical relapse-free survival.1–3 Patient and hysician preferences usually influence the treatent selection, based on a critical assessment of he relative side-effect profiles and quality-of-life valuations. Although brachytherapy alone in patients with ow-risk prostate cancer can yield excellent disease ontrol and a reported 93% 5-year freedom from iochemical failure rate, brachytherapy as monoherapy in intermediate-risk and high-risk disease Gleason score greater than 6 and/or PSA level reater than 10 ng/mL) is less than optimal.3 In the ate 1980s, Kuban et al.4 reported greater rates of ocal recurrence in men with Stage B2 or C prostate ancer and tumors of moderate and poor differeniation treated with brachytherapy alone using the etropubic implant method. With the introduction nd routine use of PSA follow-up, local control in ntermediate-risk and high-risk patients has been uch lower than previously reported. Even with odern brachytherapy techniques, intermediateisk and high-risk patients fair poorly with brachyherapy alone. In a recent report by Kwok et al.,5 he 5-year rate with iodine-125 prostate brachyherapy as monotherapy was a disappointing 63% nd 24% for intermediate-risk and high-risk paients, respectively. The combination of external beam RT (EBRT) in onjunction with a prostate brachytherapy boost has